The singular thing which neither of these companies did was:
This refers to the different techniques which a company tries to create awareness about their product or services.
With this in mind and from the knowledge of Domino and Amy's Baking Company story, we can see that they both engaged in marketing activities with the aim of improving customer satisfaction but the thing which they DID NOT do was to ignore criticism and feedback from customers.
Read more about marketing here:
https://brainly.com/question/25754149